CN115483411A - Fuel cell monomer, fuel cell, power generation system and electrical equipment - Google Patents

Abstract

The application provides a fuel cell monomer, fuel cell, power generation system and consumer belongs to the fuel cell field. The fuel cell monomer comprises an anode plate, an anode diffusion layer, a membrane electrode, a cathode diffusion layer and a cathode plate which are arranged in sequence; wherein the contact angle between the surface of one side of the cathode diffusion layer close to the cathode plate and water is theta 1, and the theta 1 is more than or equal to 90 degrees; the surface of one side of the cathode plate, which is close to the cathode diffusion layer, is provided with a hydrophilic coating, the contact angle between the surface of the hydrophilic coating and water is theta 2, and the theta 2 is not more than 50 degrees. In the fuel cell monomer, the contact angle between the surface of one side of the cathode diffusion layer close to the cathode plate and water is larger, the contact angle between the surface of the hydrophilic coating layer of the cathode plate and water is smaller, and residual water is close to the surface of the hydrophilic coating layer and easily forms film-shaped flow on the surface of the hydrophilic coating layer, so that the water drainage capacity can be improved, and the power generation performance can be improved.

Description

Fuel cell monomer, fuel cell, power generation system and electrical equipment

technical field

The present application relates to the field of fuel cells, in particular, to a fuel cell unit, a fuel cell, a power generation system and electrical equipment.

Background technique

A fuel cell is a power generation device that directly converts the chemical energy of hydrogen and oxygen into electrical energy. After the hydrogen diffuses outward through the anode and reacts, the released electrons reach the cathode and react with oxygen to form water and then discharged.

In some current fuel cells, the drainage capacity is weak, and the residual water will affect the gas reaction and reduce the rate of energy conversion, resulting in a decrease in the power generation performance of the fuel cell.

Contents of the invention

The purpose of this application is to provide a fuel cell unit, a fuel cell, a power generation system and electrical equipment, which can improve drainage capacity, thereby improving power generation performance.

The embodiment of the application is realized like this:

In the first aspect, the embodiment of the present application provides a fuel cell unit, including an anode plate, an anode diffusion layer, a membrane electrode, a cathode diffusion layer, and a cathode plate arranged in sequence;

Among them, the contact angle between the surface of the cathode diffusion layer close to the cathode plate and water is θ1, θ1≥90°; the surface of the cathode plate close to the cathode diffusion layer has a hydrophilic coating, and the contact angle between the surface of the hydrophilic coating and water The angle is θ2, θ2≤50°.

In the fuel cell monomer provided in the embodiment of the present application, the surface of the cathode diffusion layer close to the cathode plate has a larger contact angle with water, the hydrophilic coating surface of the cathode plate has a smaller contact angle with water, and the remaining water is close to the water. The surface of the water coating is easy to form a film-like flow on the surface of the hydrophilic coating, which can improve the drainage capacity and thereby improve the power generation performance.

In some embodiments, 15°≦θ2≦30°.

In some embodiments, θ1-θ2≥90°.

In some embodiments, θ1 > 120°.

In some embodiments, θ1 > 135°.

In the above-mentioned embodiment, the hydrophilicity of the surface of the hydrophilic coating, the hydrophobicity of the surface of the cathode diffusion layer near the cathode plate, or the difference between the hydrophilicity and hydrophobicity of the two are controlled according to specific standards to ensure that the residual water can be better. It is close to the surface of the hydrophilic coating and forms a film-like flow, and it is easy to realize.

In some embodiments, the hydrophilic coating comprises a reaction product of monomers grafted with electron beams and UV crosslinked.

In the above embodiments, the hydrophilicity of the hydrophilic coating can better meet the design requirements of the present application.

In a second aspect, an embodiment of the present application provides a fuel cell, including the fuel cell unit of the above embodiment, and an assembly sealing member is provided between two adjacent fuel cell units.

In a third aspect, an embodiment of the present application provides a power generation system, including the fuel cell unit of the above embodiment.

In a fourth aspect, an embodiment of the present application provides an electrical device, including the fuel cell unit of the above embodiment.

The above description is only an overview of the technical solution of the present application. In order to better understand the technical means of the present application, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and understandable , the following specifically cites the specific implementation manner of the present application.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, so It should be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

Fig. 1 is the test result diagram of the drainage capacity of some experiments provided by the application;

Fig. 2 is the test result diagram of the drainage capacity of all experiments provided by the application;

Fig. 3 is a graph showing test results of power generation capabilities of some experiments provided in this application.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all conventional products that could be purchased from the market.

It should be noted that, in the description of the present application, unless otherwise specified, the range of "value a to value b" includes both values "a" and "b".

"Multiple" in descriptions such as "multiple", "various", etc., refers to a quantity of more than 2 (including the original number 2).

"And/or" in this application, such as "feature 1 and/or feature 2", all refer to "feature 1" alone, "feature 2" alone, "feature 1" plus "feature 2" , the set of the three cases.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the application; the terms used herein are only for the purpose of describing specific embodiments, and are not intended to Limiting the Application; The terms "comprising" and "having" and any variations thereof in the specification and claims of this application are intended to cover a non-exclusive inclusion.

Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The occurrences of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is understood explicitly and implicitly by those skilled in the art that the embodiments described herein can be combined with other embodiments.

The applicant has noticed that in some current fuel cells, residual water tends to accumulate in the cathode diffusion layer below the flow field ridge of the cathode plate, which hinders mass transfer, affects the gas reaction rate, and reduces the efficiency of energy conversion. rate, resulting in a decrease in the power generation performance of the fuel cell.

In order to improve the drainage performance, in some proposals currently proposed, the flow channel of the electrode plate is usually designed with variable cross-section, that is to say, the flow channel whose cross-section changes along the direction of flow channel extension is designed. However, the shape design of the flow channel of this type of solution is complicated, and the processing difficulty and cost are relatively high.

Through in-depth research, the applicant found that when the contact angle between the surface of the diffusion layer and water is relatively large, the surface of the polar plate close to the diffusion layer is treated with a hydrophilic treatment, so that the residual water is closer to the side of the polar plate close to the diffusion layer. side surface. The improvement method is simple, and on this basis, when the hydrophilicity of the surface of the polar plate close to the diffusion layer reaches a certain standard, the residual water is easy to form a film flow on the surface of the polar plate close to the diffusion layer, which can The influence of the ridge of the flow field in the pole plate on the drainage capacity is effectively reduced, thereby improving the drainage capacity and further effectively improving the power generation performance.

Based on the above studies, the fuel cell unit, fuel cell, power generation system and electrical equipment of the present application will be described in detail below in conjunction with specific embodiments.

In the first aspect, the embodiment of the present application provides a fuel cell unit, including an anode plate, an anode diffusion layer, a membrane electrode, a cathode diffusion layer, and a cathode plate arranged in sequence;

Among them, the contact angle between the surface of the cathode diffusion layer close to the cathode plate and water is θ1, θ1≥90°; the surface of the cathode plate close to the cathode diffusion layer has a hydrophilic coating, and the contact angle between the surface of the hydrophilic coating and water The angle is θ2, θ2≤50°.

A fuel cell cell is a small unit in a fuel cell that has a complete energy conversion function; a battery module with higher power, that is, a fuel cell, can be obtained by combining at least two fuel cell cells.

Anode plates and cathode plates are also called bipolar plates, collector plates, flow field plates, etc., and the side close to the corresponding diffusion layer can be designed with flow fields, air inlets and drains as required. As an example, in the embodiments provided in the present application, a flow field containing a plurality of straight-through channels distributed in parallel is provided on the side of each electrode plate close to the corresponding diffusion layer; wherein, the flow channels are the grooves of the flow field, The space between the channels is the ridge of the flow field.

The hydrophilic coating refers to a hydrophilic film layer coated on the surface of the cathode plate near the cathode diffusion layer, such as at least completely covering the surface of the cathode plate near the cathode diffusion layer. Flow field area; in order to meet the design requirements for θ2 in this application, the material of the hydrophilic coating can be directly selected according to the requirements, manufactured with reference to the existing technology, or newly designed.

The anode diffusion layer and the cathode diffusion layer, also known as the gas diffusion layer, play the role of supporting the catalytic layer, collecting current, conducting gas and discharging reaction product water in the fuel cell monomer. The materials are, for example, carbon fiber paper, carbon fiber woven cloth, non- Woven cloth, carbon black paper, etc., because the surface of the diffusion layer of the above materials usually has a large contact angle with water, in order to meet the design requirements for θ1 in this application, the material of the cathode diffusion layer can be directly selected according to this requirement .

Membrane electrodes, also known as proton exchange membranes, have the function of blocking and conducting protons, such as fluorosulfonic acid proton exchange membranes, nafion recast membranes, non-fluoropolymer proton exchange membranes, and new composite proton exchange membranes.

It should be noted that in this application, the fuel cell unit can also be configured with other conventional structures such as end plates, catalytic layers, sealing gaskets, sealing rings, etc. as required. in. The end plate is arranged on the outside of the anode plate and the cathode plate; the catalytic layer is arranged between the diffusion layer and the membrane electrode; the sealing gasket and the sealing ring are used for sealing between the electrode plate and the membrane electrode, and the diffusion layer is nested inside it.

In the fuel cell monomer provided in the embodiment of the present application, the surface of the cathode diffusion layer close to the cathode plate has a larger contact angle with water, and the surface of the hydrophilic coating of the cathode plate has a smaller contact angle with water. This improvement method is simple. Moreover, the residual water is close to the surface of the hydrophilic coating and is easy to form a film-like flow on the surface of the hydrophilic coating, which can effectively reduce the impact of the ridge of the flow field in the plate on the drainage capacity, and can improve the drainage capacity, thereby improving power generation. performance.

According to research, when θ2 is gradually reduced, starting from θ2 reduced to 50°, the length of residual liquid water spreading on the surface of the cathode plate near the cathode diffusion layer increases significantly, and can reach more than 5mm. Among them, when θ2 is reduced to 30°, the length of residual liquid water spreading on the surface of the cathode plate near the cathode diffusion layer is further significantly increased, reaching nearly 10mm; as θ2 is reduced to 15°, the residual liquid water The length of the liquid water spreading on the surface of the cathode plate close to the cathode diffusion layer can even be increased to nearly 15mm, which has a good performance of forming a film-like flow.

Under the experimental conditions with a current density of 0.3A/cm ² , compared with the drainage capacity of 0.1g/s for the formation of occluded flow in the flow field and the maximum drainage capacity of about 0.1g/s for the formation of droplet flow in the flow field , the drainage capacity can be increased to close to 0.2g/s or above 0.2g/s under the state of film flow in the flow field, and even can be increased to close to 0.5g/s in the preferred solution.

In some embodiments, 15°≤θ2≤30°, the value of θ2 is, for example but not limited to, any one of 15°, 20°, 25°, 30°, etc. or a range between any two.

In some embodiments, θ1-θ2≥90°, the difference between the two is, for example but not limited to, 90°, 95°, 100°, 105°, 110°, 105°, 110°, 115°, 120°, Any one of 125°, etc. or any range between the two.

In some embodiments, θ1≥120°; in some embodiments, θ1≥135°; as an example, the value of θ1 is, for example but not limited to, any one of 120°, 125°, 130°, 135°, etc. or any range in between.

In the above-mentioned embodiment, the hydrophilicity of the surface of the hydrophilic coating, the hydrophobicity of the surface of the cathode diffusion layer near the cathode plate, or the difference between the hydrophilicity and hydrophobicity of the two are controlled according to specific standards to ensure that the residual water can be better. It is close to the surface of the hydrophilic coating and forms a film-like flow, and it is easy to realize.

In some embodiments, the hydrophilic coating comprises a reaction product of monomers grafted with electron beams and UV crosslinked. In the above embodiments, the hydrophilicity of the hydrophilic coating can better meet the design requirements of the present application.

As an example, specific reference can be made to the hydrophilic treatment method in the patent application with the application number CN201310316785.9.

The hydrophilic coating includes a first grafted substance, a second grafted substance and a third grafted substance. Wherein, the first grafting substance includes a reaction product obtained by electron beam grafting and UV crosslinking of grafting monomers having acrylate groups and photoinitiator groups. The second grafted species comprises the reaction of one or more monomers having at least one acrylate group and at least one additional ethylenically unsaturated radically polymerizable group via electron beam grafting and UV crosslinking product. The third grafted substance is a reaction product obtained by electron beam grafting and UV crosslinking of one or more additional monomers having at least one ethylenically unsaturated free radical polymerizable group and hydrophilic group. At least one of the monomers forming the second grafted species and the third grafted species is hydrophilic.

In the preparation process of the hydrophilic coating, the electron beam irradiation step facilitates the subsequent UV-initiated cross-linking curing. The electron beam irradiation step employs, for example, an apparatus including an electron beam source. The UV curing step is performed, for example, under an inert atmosphere (nitrogen, carbon dioxide, helium, argon, etc.), and the UV light source can be of two types: 1) a relatively low-intensity light source, such as a backlight, at a wavelength of 280nm to 400nm 2) Relatively high-intensity light sources, such as medium-pressure mercury lamps, typically provide an intensity greater than ^{10 mW/cm 2 .} In cases where actinic radiation is used to fully or partially crosslink the oligomer composition, high intensities and short exposure times are preferred. For example, an intensity of 600 mW/ ^cm2 and an exposure time of about 1 s can be used successfully.

In a second aspect, an embodiment of the present application provides a fuel cell, comprising at least two fuel cell cells of the above-mentioned embodiments, and an assembly sealing member is provided between two adjacent fuel cell cells.

In the fuel cell, the arrangement of two adjacent fuel cell cells is not limited, for example, they are stacked and arranged in a conventional manner along the thickness direction of the fuel cell cells. The assembly seal is used to seal the junction of two adjacent fuel cell cells. between the edges of the end plates.

In a third aspect, an embodiment of the present application provides a power generation system, including the fuel cell unit of the above embodiment.

The power generation system uses the fuel cell unit as part or all of the power generation module, and it can also be configured with power distributors, energy storage systems, inverters, power sensors, control devices and other functional modules in a conventional manner as required.

In a fourth aspect, an embodiment of the present application provides an electrical device, including the fuel cell unit of the above embodiment.

Electrical equipment can be in various forms, such as mobile phones, portable devices, notebook computers, battery cars, electric vehicles, ships, spacecraft, electric toys, and electric tools.

The fuel cell unit, fuel cell, power generation system and electrical equipment of the present application will be described in detail below in conjunction with specific embodiments.

1. Provide fuel cell monomers

(1) Provide a cathode plate. For experiments that require hydrophilic modification, form a hydrophilic coating with a specific θ2 value in the manner of electron beam grafting and UV crosslinking in the above detailed description.

(2) Select a cathode diffusion layer with a specific value of θ1.

(3) The cathode plate in (1), the cathode diffusion layer, the membrane electrode, the anode diffusion layer, and the anode plate in (2) are sequentially arranged to assemble a fuel cell unit.

in:

The fuel cell model refers to the Toyota MIRAI2 generation single cell.

The difference between each group of experiments is: the contact angle between the surface of the cathode diffusion layer close to the cathode plate and water, and/or whether there is a hydrophilic coating on the surface of the cathode plate close to the cathode diffusion layer, and whether the cathode plate is close to the cathode plate. The contact angle between one side of the cathode diffusion layer and water. The above-mentioned conditions of each experiment are shown in Table 1.

Table 1

Wherein, in the experiment where the surface of the cathode plate has a hydrophilic coating, the water contact angle on the surface of the cathode plate is the water contact angle on the surface of the hydrophilic coating.

2. Test fuel cell performance

(1) Drainage capacity test

Test Methods:

The fuel cell model refers to the Toyota MIRAI2 generation single cell. Detect the displacement of the water outlet as an indicator of the drainage capacity.

The test conditions include: the detection temperature is 70°C, the anode intake air pressure is 220Kpa, the cathode intake air pressure is 230Kpa, the anode intake air metering ratio is 1.25, the cathode air intake metering ratio is 1.5, the anode intake air is humidified and the temperature is 45°C, the cathode intake air is without humidify.

The test results of the drainage capacity of the fuel cells corresponding to each experimental group are shown in FIGS. 1-2 .

According to Table 1 and Figures 1-2, it can be seen that:

In the fuel cell monomer provided in the embodiment, the water contact angle on the surface of the cathode plate is small and the water contact angle on the surface of the cathode diffusion layer is relatively large, and the drainage capacity is strong.

Compared with Example 1 and Example 2, the surface of the cathode diffusion layer has better hydrophobicity, so that the drainage capacity is further enhanced.

Compared with Example 1, Comparative Example 1 has no hydrophilic modification on the surface of the cathode plate, and the drainage capacity is obviously reduced.

Compared with Example 1, Comparative Example 2 has no hydrophilic modification on the surface of the cathode plate, and the water contact angle on the surface of the cathode diffusion layer is relatively small, and the drainage capacity is further significantly reduced.

(2) Generator voltage test

Test Methods:

The fuel cell model refers to the Toyota MIRAI2 generation single cell.

The test conditions include: the detection temperature is 70°C, the anode intake air pressure is 220Kpa, the cathode intake air pressure is 230Kpa, the anode intake air metering ratio is 1.25, the cathode air intake metering ratio is 1.5, the anode intake air is humidified and the temperature is 45°C, the cathode intake air is without humidify.

The test results of the power generation capacity of the fuel cells corresponding to each experimental group are shown in FIG. 3 .

According to Table 1 and Figure 3, it can be seen that:

In the fuel cell monomer provided in the embodiment, the water contact angle on the surface of the cathode plate is small and the water contact angle on the surface of the cathode diffusion layer is relatively large, so the power generation capacity is relatively strong.

Compared with Example 1 and Example 2, the surface of the cathode diffusion layer has better hydrophobicity, so that the power generation capacity is further enhanced.

Compared with Example 1, Comparative Example 1 has no hydrophilic modification on the surface of the cathode plate, and the power generation capacity is obviously reduced.

Compared with Example 1, Comparative Example 2 has no hydrophilic modification on the surface of the cathode plate, and the water contact angle on the surface of the cathode diffusion layer is relatively small, and the power generation capacity is further significantly reduced.

The embodiments described above are some of the embodiments of the present application, but not all of them. The detailed description of the embodiments of the application is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the application. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this application.

Claims (9)

1. A single fuel cell, characterized in that it comprises an anode plate, an anode diffusion layer, a membrane electrode, a cathode diffusion layer and a cathode plate arranged in sequence; Wherein, the contact angle between the surface of the cathode diffusion layer close to the cathode plate and water is θ1, θ1≥90°; the surface of the cathode plate close to the cathode diffusion layer has a hydrophilic coating, so The contact angle between the hydrophilic coating surface and water is θ2, θ2≤50°. 2. The fuel cell unit according to claim 1, characterized in that 15°≤θ2≤30°. 3. The fuel cell unit according to claim 1 or 2, characterized in that θ1-θ2≥90°. 4. The fuel cell unit according to claim 1 or 2, characterized in that θ1≥120°. 5. The fuel cell unit according to claim 4, characterized in that θ1≥135°. 6. The fuel cell monomer according to claim 1 or 2, characterized in that the hydrophilic coating contains a reaction product obtained by electron beam grafting and UV crosslinking of the monomer. 7. A fuel cell, characterized in that it comprises at least two fuel cell cells according to any one of claims 1 to 6, and an assembly seal is provided between two adjacent fuel cell cells . 8. A power generation system, characterized by comprising the fuel cell unit according to any one of claims 1-6. 9. An electrical device, characterized by comprising the fuel cell unit according to any one of claims 1-6.

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